A compressor compresses a gas by converting electric energy into kinetic energy. According to a compression mechanism compressing a gas, there are various types of compressors such as a rotary compressor, a scroll compressor, a reciprocal compressor and the like.
As for the reciprocating compressor, when a driving motor generates a driving force, a piston constituting a compression unit linearly reciprocates within a cylinder upon receiving the driving force, thereby drawing in, compressing and discharging a gas. There are a method in which a driving motor generates a rotating force and the rotating force is transferred to a piston through a crank shaft and a method in which the driving motor generates a linear reciprocating driving force and the linear reciprocating driving force is transferred to the piston.
In the reciprocating compressor, when the piston linearly reciprocates within a cylinder upon receiving a driving force of the driving motor, an intake valve and a discharge valve are opened and closed by a pressure difference inside the cylinder according to the reciprocation of the piston, and thusly a gas is taken into the cylinder, compressed and discharged.
FIG. 1 is a sectional view that illustrates one example of a discharge valve assembly of a reciprocating compressor.
As illustrated, the discharge valve assembly of the reciprocating compressor includes a discharge cover 20 covering an inner space of the cylinder 10, a discharge valve 30 inserted in the discharge cover 20 and opening and closing the inner space of the cylinder 10, and a valve spring 40 elastically supporting the discharge valve 30.
The discharge cover 20 includes a cylindrical portion 21 having certain length and outer diameter and having a space therein, a fixing portion 22 bent and extending from one side of the cylindrical portion 21 and coupled to a front frame (not shown), and a discharge hole 23 formed at the cylindrical portion 21 and coupled to a gas discharge pipe 50 through which a gas is discharged.
The discharge valve 30 has a disc shape with a certain thickness, and the valve spring 40 is a cylindrical coil spring having a certain length.
Undescribed reference numeral 60 is a piston and 70 is a suction valve:
The operation of the discharge valve assembly of such a reciprocating compressor will now be described.
The piston 60 linearly reciprocates upon receiving a driving force of the driving motor (not shown). First, when the piston 60 moves from a top dead point to a bottom dead point, as shown in FIG. 2, the discharge valve 30 is closely attached to a contact surface of the cylinder 10 by a pressure difference inside the cylinder and simultaneously, the suction valve 70 is opened so as to allow the introduction of a gas into the inner space of the cylinder through a flow path formed in the piston 60.
If the piston 60 moves from the bottom dead point to the top dead point, the suction valve 70 blocks the flow path of the piston 60, thereby gradually compressing a gas received in the inner. space of the cylinder 10. Then, the gas reaches a set compression state, the discharge valve 30 supported by the valve spring 40 is opened, discharging the compressed gas. Such processes are continuously repeated, to thereby compress a gas.
In the aforementioned discharge valve assembly, the discharge valve 30 that opens and closes an inner space of the cylinder 10 and discharges a gas continuously comes in contact with a contact surface of the cylinder 10 and also is influenced by high pressure at the time of introduction and discharge of the gas. If the discharge valve 30 is deformed or abraded by the pressure applied to the discharge valve 30 and the impact due to continuous contact with the contact surface of the cylinder 10, the leakage of a gas occurs and the compression efficiency is degraded. Accordingly, those issues must be considered in designing the discharge valve 30.
If a volume of the discharge valve 30 is increased or a material having great strength is used for the discharge valve 30 in order to prevent deformation of the discharge valve 30 due to the pressure applied thereto, the amount of impact occurring when the discharge valve 30 continuously comes in contact with the contact surface of the cylinder 10 is increased, which causes contact noise and damage to the discharge valve 30.